SkPDF: clean up fRasterDpi

  - PDFDevice no longer has a fRasterDpi; simply queries document.
  - #define DPI_FOR_RASTER_SCALE_ONE becomes constexpr float.
  - PDFShader::GetPDFShader no longer takes rasterScale or dpi
  - Remove un-needed factory functions.  We're all adults here.

Change-Id: Id2ce75d4e61af385763ccfb1db210465a1600067
Reviewed-on: https://skia-review.googlesource.com/21348
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/src/pdf/SkPDFDevice.h b/src/pdf/SkPDFDevice.h
index ad44bcd..8d2c511 100644
--- a/src/pdf/SkPDFDevice.h
+++ b/src/pdf/SkPDFDevice.h
@@ -33,53 +33,42 @@
 class SkPDFStream;
 class SkRRect;
 
-/** \class SkPDFDevice
-
-    The drawing context for the PDF backend.
-*/
+/**
+ *  \class SkPDFDevice
+ *
+ *  An SkPDFDevice is the drawing context for a page or layer of PDF
+ *  content.
+ */
 class SkPDFDevice final : public SkClipStackDevice {
 public:
-    /** Create a PDF drawing context.  SkPDFDevice applies a
-     *  scale-and-translate transform to move the origin from the
-     *  bottom left (PDF default) to the top left (Skia default).
+    /**
      *  @param pageSize Page size in point units.
      *         1 point == 127/360 mm == 1/72 inch
-     *  @param rasterDpi the DPI at which features without native PDF
-     *         support will be rasterized (e.g. draw image with
-     *         perspective, draw text with perspective, ...).  A
-     *         larger DPI would create a PDF that reflects the
-     *         original intent with better fidelity, but it can make
-     *         for larger PDF files too, which would use more memory
-     *         while rendering, and it would be slower to be processed
-     *         or sent online or to printer.  A good choice is
-     *         SK_ScalarDefaultRasterDPI(72.0f).
-     *  @param SkPDFDocument.  A non-null pointer back to the
-     *         document.  The document is repsonsible for
+     *  @param document  A non-null pointer back to the
+     *         PDFDocument object.  The document is repsonsible for
      *         de-duplicating across pages (via the SkPDFCanon) and
      *         for early serializing of large immutable objects, such
      *         as images (via SkPDFDocument::serialize()).
      */
-    static sk_sp<SkPDFDevice> Make(SkISize pageSize, SkScalar rasterDpi, SkPDFDocument* doc) {
-        return sk_sp<SkPDFDevice>(new SkPDFDevice(pageSize, rasterDpi, doc, true));
-    }
+    SkPDFDevice(SkISize pageSize, SkPDFDocument* document);
 
-    /** Create a PDF drawing context without fipping the y-axis. */
-    static sk_sp<SkPDFDevice> MakeUnflipped(SkISize pageSize,
-                                            SkScalar rasterDpi,
-                                            SkPDFDocument* doc) {
-        return sk_sp<SkPDFDevice>(new SkPDFDevice(pageSize, rasterDpi, doc, false));
-    }
+    /**
+     *  Apply a scale-and-translate transform to move the origin from the
+     *  bottom left (PDF default) to the top left (Skia default).
+     */
+    void setFlip();
 
     sk_sp<SkPDFDevice> makeCongruentDevice() {
-        return sk_sp<SkPDFDevice>(new SkPDFDevice(fPageSize, fRasterDpi, fDocument, false));
+        return sk_make_sp<SkPDFDevice>(fPageSize, fDocument);
     }
 
     ~SkPDFDevice() override;
 
-    /** These are called inside the per-device-layer loop for each draw call.
-     When these are called, we have already applied any saveLayer operations,
-     and are handling any looping from the paint, and any effects from the
-     DrawFilter.
+    /**
+     *  These are called inside the per-device-layer loop for each draw call.
+     *  When these are called, we have already applied any saveLayer
+     *  operations, and are handling any looping from the paint, and any
+     *  effects from the DrawFilter.
      */
     void drawPaint(const SkPaint& paint) override;
     void drawPoints(SkCanvas::PointMode mode,
@@ -212,15 +201,9 @@
     };
     SkSinglyLinkedList<ContentEntry> fContentEntries;
 
-    SkScalar fRasterDpi;
-
     SkPDFDocument* fDocument;
-    ////////////////////////////////////////////////////////////////////////////
 
-    SkPDFDevice(SkISize pageSize,
-                SkScalar rasterDpi,
-                SkPDFDocument* doc,
-                bool flip);
+    ////////////////////////////////////////////////////////////////////////////
 
     SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;